Small diameter cartridge design for a surgical stapling instrument

ABSTRACT

An end effector includes a first jaw, a second jaw, and a cartridge. The first cartridge includes a sled and the second jaw includes an anvil. The first and second jaws are moveable relative to one another. The cartridge is disposed on the first jaw and has a plurality of staples. The sled is configured to engage each staple to the plurality of staples to eject the plurality of staples from the cartridge as the sled is longitudinally translated through the cartridge. A loading unit is also disclosed including an elongated body and an end effector that is articulable relative to the end effector. The end effector and the elongated body of the loading unit are configured to pass or fit through a 5 mm opening.

BACKGROUND

1. Technical Field

The present disclosure relates to surgical instruments and, morespecifically, to staple cartridges for surgical stapling instrumentshaving a reduced diameter.

2. Discussion of Related Art

Surgical stapling devices for stapling tissue typically include a toolassembly having a staple cartridge, an anvil, and a knife that can beactuated to effect simultaneous dissection and suturing of tissue. Whencompared to traditional methods of manually applying threaded sutures totissue, the use of surgical stapling devices to suture and dissecttissue has increased the speed of the suturing procedure and thus,minimized patient trauma.

In an endoscopic surgical procedure, a surgical stapler is insertedthrough a small incision in the skin or through a cannula to access asurgical site. Due to the complexity of known surgical stapling devices,a continuing need exists for small diameter surgical stapling devicesthat are suitable for insertion through smaller diameter openings, e.g.,a 5 mm cannula, that can effectively suture and dissect tissue.

SUMMARY

In an aspect of the present disclosure, an end effector includes a firstjaw, a second jaw, and a cartridge. The first jaw has a sled and thesecond jaw has an anvil. The first and second jaws are moveable relativeto one another. The cartridge is disposed on the first jaw and has aplurality of staples. The sled is configured to engage each staple ofthe plurality of staples to eject the plurality of staples from thecartridge as the sled is longitudinally translated through thecartridge. The end effector may have an approximated configuration suchthat the end effector is configured to fit through a 5 mm opening. Thesled may be configured to directly engage each staple of the pluralityof staples.

In aspects, the cartridge may define a plurality of vertical slots and afirst vertical channel. The lower jaw may define a longitudinal axiswith the first vertical channel parallel to the longitudinal axis. Thevertical channel may pass through each vertical slot of a first line ofthe plurality of vertical slots.

In some aspects, a staple of the plurality of staples is disposed ineach vertical slot of the plurality of vertical slots. The cartridge andthe first jaw may define a sled channel and the sled may belongitudinally translatable through the sled channel. The sled mayinclude a first fin that extends from an upper surface of the sled. Thefirst fin may be translatable through the first vertical channel toengage each staple disposed within the vertical slots of the first lineof the plurality of vertical slots.

In certain aspects, each vertical slot of the plurality of verticalslots has a first width transverse to the longitudinal axis and thefirst vertical channel has a second width transverse to the longitudinalaxis. The second width may be less than the first width. The staple ofthe plurality of staples may be disposed in each vertical slot of theplurality of vertical slots and has a stapled width that is transverseto the longitudinal axis. The staple width may be less than the firstwidth and greater than the second width such that each staple is limitedto movement towards and way from a tissue contacting surface of thecartridge. Each staple of the plurality of staples may include legs thatare connected by a backspan. The backspan may have a chamfered surfaceon a proximal end of the backspan. The chamfered surface may be disposedat a chamfer angle relative to a bottom surface of the backspan. Thesled may include a first fin and may have a first angled surface that isconfigured to engage the chamfered surface of each staple of theplurality of staples as the sled is translated through the cartridge.The first angle may be equal to the chamfer angle. The first fin mayinclude a second angled surface that is proximal of the first angledsurface. The second angled surface may define a second angle with theupper surface of the sled. The second angle may be greater than thefirst angle. The second angled surface may be configured to engage thechamfered surface of each staple subsequent to the first angled surfaceengaging the chamfered surface of each staple.

In another aspect of the present disclosure, a loading unit includes anelongated body and an end effector that is disposed at a distal end ofthe elongated body. The end effector may be any of the end effectorsdetailed herein.

In aspects, the elongated body is configured to fit through a 5 mmopening. The end effector may be articulable relative to the elongatedbody. The elongated body may include a proximal end that is configuredto couple the loading unit to a handle. The handle may be manuallyactuated or electromechanically actuated.

In another aspect of the present disclosure, a method of joining tissueincludes clamping tissue between first and second jaws of a surgicalinstrument and translating a sled through a cartridge of the first jaw.The sled contacting each staple of a plurality of staples to eject theplurality of staples from the cartridge towards the second jaw.

In aspects, translating the sled through the cartridge includestranslating the sled through a sled channel that is defined by the firstjaw and the cartridge such that a first fin which extends from an uppersurface of the sled contacts each of the plurality of staples.Translating the sled through the cartridge may include translating thefirst fin though a vertical channel and a first line of vertical slotsdefined by the cartridge. The first line of vertical slots may bedisposed along the vertical channel. Contacting each staple of theplurality of staples with the first fin may include contacting achamfered surface of each staple of the plurality of staples with afirst angled surface of the first fin and subsequently contacting thechamfered surface of each staple of the plurality of staples with asecond angled surface of the first fin. Contacting the chamfered surfaceof each staple of the plurality of staples with the first angled surfaceejects each staple of the plurality of staples from the cartridge suchthat legs of the staple penetrate tissue between the first and secondjaws. Contacting the chamfered surface of each staple of the pluralityof staples with the second angled surface drives the legs of each stapleof the plurality of staples into the angle to deform the legs to jointhe tissue.

Further, to the extent consistent, any of the aspects described hereinmay be used in conjunction with any or all of the other aspectsdescribed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the present disclosure are described hereinbelow withreference to the drawings, which are incorporated in and constitute apart of this specification, wherein:

FIG. 1A is a perspective view of a manually actuated surgical instrumentand a loading unit provided in accordance with the present disclosure;

FIG. 1B is a perspective view of a powered surgical instrument andanother loading unit provided in accordance with the present disclosure;

FIG. 2 is an enlarged view of the indicated area of detail of FIG. 1Ashowing an end effector of the loading unit of FIG. 1A in a spaced-apartconfiguration;

FIG. 3 is a perspective view of the end effector of FIG. 2 in anapproximated configuration;

FIG. 4 is a cross-sectional view taken along the section line 4-4 ofFIG. 3;

FIG. 5 is a cross-sectional view taken along the section line 5-5 ofFIG. 4;

FIG. 6 is a top view of a tissue contacting surface of a cartridge ofthe end effector of FIG. 2;

FIG. 7 is a perspective view of a staple of the cartridge of FIG. 6;

FIG. 8 is a side view of a sled of the end effector of FIG. 4;

FIG. 9A is a perspective view of the sled of FIG. 8;

FIG. 9B is a perspective view of another sled in accordance with thepresent disclosure; and

FIG. 10 is a cross-sectional view of the end effector of FIG. 4 with thesled translated through the cartridge to eject the staples from thecartridge.

DETAILED DESCRIPTION

Embodiments of the present disclosure are now described in detail withreference to the drawings in which like reference numerals designateidentical or corresponding elements in each of the several views. Asused herein, the term “clinician” refers to a doctor, a nurse, or anyother care provider and may include support personnel. Throughout thisdescription, the term “proximal” refers to the portion of the device orcomponent thereof that is closest to the clinician and the term “distal”refers to the portion of the device or component thereof that isfarthest from the clinician.

This disclosure relates generally to a loading unit for joining tissuewith staples. The loading unit is sized to fit through a 5 mm opening orport and includes an end effector having upper and lower jaws. The lowerjaw has a staple cartridge with a plurality of staples disposed therein.The lower jaw also includes a sled that is translatable through thecartridge such that the sled directly engages each staple to eject thestaples from the cartridge and to drive the staples into an anvil of theupper jaw to form the staples.

Referring now to FIGS. 1A and 1B, a manually actuated surgicalinstrument 101 and a powered surgical instrument 201 each include aloading unit 10 provided in accordance with the present disclosure. Themanually actuated surgical instrument 101 includes a housing 110, ahandle assembly 112, a rotation control 114, an actuation lever 116, aretraction control 118, and an elongated portion 120. The elongatedportion 120 extends from the housing 110 to support the loading unit 10at a distal end 122 thereof.

For a detailed description of the structure and function of an exemplarymanually actuated surgical instrument reference may be made to U.S. Pat.No. 7,565,993, the entire contents of which are incorporated byreference herein.

The powered surgical instrument 201 includes a powered handle 210 and anadapter 220. The powered handle 210 includes a user interface 212 and anadapter interface 214. The adapter 220 includes a distal end 222 that isconfigured to support the loading unit 10 and a proximal connector 224that is configured to be received in the adapter interface 214 of thepowered handle 210. For a detailed description of the structure andfunction of an exemplary powered handle and adapter reference may bemade to U.S. Patent Publication No. 2012/0253329, the entire contents ofwhich are incorporated by reference herein.

As seen in FIG. 1B, a loading unit 10′ includes an elongated body 20 andan end effector 30. The elongated body 20 includes a connector 22 thatreleasably couples to the distal end 122 of the elongated portion 120(FIG. 1A) or the distal end 222 of the adapter 220 (FIG. 1B). Theconnector 22 includes tabs 24 that align and secure the connector withthe elongated portion 120 or the adapter 220. The connector 22 isconfigured to interface with one or more drive rods, e.g., drive rod 226of the adapter 226, to actuate one or more functions of the end effector30 as detailed below. The elongated body 20 of the loading unit 10′ mayhave a diameter of about 5 mm such that the elongated body 20 may fitthrough a 5 mm cannula or access port. It is also contemplate that theloading unit 10, 10′ may be coupled to a robotic surgical system. For adetailed description of the structure and function of an exemplaryrobotic surgical system reference may be made to U.S. Pat. No.8,828,023, the entire contents of which are hereby incorporated byreference

With continued reference to FIG. 1B, the loading unit 10′ includes adissecting tip 310 on the upper jaw 90′. The dissecting tip 310 isconfigured to pierce tissue, penetrate tissue, maneuver tissue, ordissect tissue. The dissecting tip 310 may be releasably secured to theupper jaw 90′ or may be integrally formed with the upper jaw 90′. For adetailed description of the structure and function of an exemplarydissecting tip reference may be made to U.S. Pat. No. 8,496,153, theentire contents of which are hereby incorporated by reference.

The loading unit 10′ may also include a buttress 322 on the lower jaw 40and/or a buttress 324 on the upper jaw 90′. The buttresses 322, 324 arereleasably attached to tissue contacting surfaces of the lower jaw 40and the upper jaw 90′, respectively, to aid in joining tissue together.The buttress 322, 324 may be bioabsorbable and may include medicant topromote healing of tissue joined by the end effector 30. For a detaileddescription of the structure and function of an exemplary buttressreference may be made to U.S. Pat. No. 8,496,683, the entire contents ofwhich are hereby incorporated by reference.

With additional reference to FIGS. 2-4, the end effector 30 includes afirst or lower jaw 40 and a second or upper jaw 90 that are moveablerelative to one another between a spaced apart configuration (FIG. 2)and an approximated configuration (FIG. 3) to grasp tissue therebetween.In the approximated configuration, the end effector 30 may have adiameter of about 5 mm such that the end effector 30 may fit through a 5mm cannula or access port. The lower jaw 40 includes a cartridge 50having a plurality of staples 60 and the upper jaw 90 includes an anvil92 defining a plurality of staple pockets 94. The cartridge 50 may bereleasably coupled to the lower jaw 40. Alternatively, the cartridge 50may be integrally formed with the lower jaw 40.

With particular reference to FIG. 1A, to actuate the end effector 30 ofthe loading unit 10 with the manually actuated surgical instrument 101,the proximal end 22 (FIG. 1B) is received in a distal end 122 of theelongated portion 120 to couple the loading unit 10 to the housing 110.Then the handle assembly 112 is actuated to move the end effector 30 tothe approximated configuration and to eject staples 60 (FIG. 4) from thecartridge 50 (FIG. 4). Specifically, a moveable handle of the handleassembly 112 is drawn towards a stationary handle of the handle assembly112 to advance a drive rod (not shown) of the surgical instrument 101 tomove the end effector 30 to the approximated configuration. Next, themoveable handle is returned to an unactuated position while the driverod remains substantially stationary. Then, the moveable handle isactuated a second time to further advance the drive rod which ejects thestaples 60 from the cartridge 50 and/or to advance a knife (notexplicitly shown), as detailed below.

With particular reference to FIG. 1B, to actuate the end effector 30 ofthe loading unit 10 with the powered surgical instrument 201, theproximal connector 224 of the adapter 220 is received within the adapterinterface 214 of the powered handle 210 to couple the adapter 220 to thepowered handle 210. The loading unit 10 is coupled to the adapter 220 bypositioning the connector 22 of the loading unit 10 within the distalend 222 of the adapter 220 such that the drive rod 226 of the adapter isreceived within the connector 22 of the loading unit. The user interface212 is then manipulated to advance the drive rod 226 which firstapproximates the end effector 30 and then ejects the staples 60 (FIG. 4)from the cartridge 50 (FIG. 4) as detailed below.

Referring to FIGS. 4-6, the cartridge 50 defines a plurality of verticalslots 52, longitudinal vertical channels 54, a longitudinal knifechannel 56, and a longitudinal sled channel 58 that passes through alower portion of each of the vertical slots 52, vertical channels 54,and knife channel 56. The knife channel 56 is disposed along alongitudinal axis of the end effector 30. With particular reference toFIG. 6, the vertical slots 52 are arranged in longitudinal rows whichare laterally offset from and parallel to the knife channel 56. Each ofthe vertical channels 54 passes through one of the longitudinal rows ofvertical slots 52. The vertical slots 52 have a first width W₁,transverse to the longitudinal axis of the end effector 30, and thevertical channels 54 have a second width W₂, transverse to thelongitudinal axis of the end effector 30, that is smaller than the firstwidth W₁. Each of the vertical slots 52 receives a staple 60 having awidth less than the first width W₁ and greater than the second width W₂such that each staple 60 is retained within a respective vertical slot52. Each vertical slot 52 is sized to slidably and releasable retain astaple 60. The vertical channel 54 is sized to receive and guide a fin44 (FIG. 9) of a sled 42 as the sled 42 is longitudinally translatedthrough the cartridge 50 as detailed below. Further, the fin 44 has awidth that is less than a width of the staple 60 as detailed below.

With reference to FIG. 7, each staple 60 includes legs 62 joinedtogether by a backspan 64. The legs 62 extend from the backspan 64 totips 63 which are configured to penetrate tissue. As shown, the tips 63are angled to penetrate tissue; however, it is contemplated that thetips 63 may have a conical shape or another shape suitable forpenetrating tissue. The backspan 64 includes a chamfered surface 66 onat least a proximally facing end when the staple 60 is disposed within arespective vertical slot 52 (FIG. 6). It is contemplated that each endof the backspan 64 may include a chamfered surface 66 as detailed abovesuch that the staples 60 may be positioned in the vertical slots witheither end of the backspan 64 facing proximally. The chamfered surface66 defines a chamfer angle θ with a lower surface 65 a of the backspan64. The chamfer angle θ is in the range of about 5° to about 35° (e.g.,about 30°). It is contemplated that each longitudinal row of verticalslots 52 may be sized to receive staples 60 having the same or differentdimensions; e.g., length of the legs 62, length of the backspan 64, orwidth of the legs 62 and backspan 64; from staples 62 of anotherlongitudinal row of vertical slots 52.

In any of the embodiments disclosed herein, the feature on the backspan64 can be chamfers, rounds, protrusions, one or more bevels, etc., thatwould engage the sled surface and arranged so that the staple is pushedout of the cartridge.

The backspan 64 of each staple 60 is thicker than a backspan of atraditional staple and functions as a pusher for the respective staple60. By having the backspan 64 function as a pusher, traditional pushersmay be eliminated from the staple cartridge 50 which allows the staplecartridge 50 to have a smaller diameter than a traditional staplecartridge. The backspan 64 is substantially rectangular in cross-sectionwith vertical side surfaces 65 b and a length substantially equal to alongitudinal length of a respective vertical slot 52 such that thebackspan 64 is configured to guide the staple 60 within the respectivevertical slot 52 as detailed below.

Referring briefly back to FIG. 4, the lower jaw 40 includes a sled 42that is slidable through the sled channel 58 of the cartridge 50 toeject the staples 60 from the cartridge 50. With reference to FIGS. 8and 9A, the sled 42 includes a horizontal base 43 and one or more fins44 extending vertically from the base 43. Each fin 44 is slidablethrough a vertical channel 54 of the cartridge 50 and has a first angledsurface 45 a and a second angled surface 45 b positioned distal to thefirst angled surface 45 a. The first angled surface 45 a issubstantially linear and defines a first angle α with the base 43 of thesled 42. The second angled surface 45 b is substantially linear anddefines a second angle γ relative to the base 43 of the sled 42. Thefirst angle α is substantially equal to the chamfer angle θ of thechamfered surface 66 of the backspan 64 of each staple 60. The secondangle γ is greater than the first angle α. The first angle α may in arange of about 5° to about 35° (e.g., 30°) and the second angle γ may bein a range of about 25° to about 45° (e.g., about 40°). For a detaileddiscussion of the sleds with first and second angles reference may bemade to U.S. Pat. No. 7,635,074 (“the '074 Patent), the entire contentsof which are hereby incorporated by reference.

As shown, the sled 42 is configured to be positioned on one side of theknife channel 56 and the lower jaw 40 may include another sled 42disposed on either side of the knife channel 56. The sled 42 includestwo fins 44 such that as the base 43 translated through the sled channel58, each fin 44 slides or translates through a respective verticalchannel 54 to eject staples 60 positioned within the vertical slots 52aligned with the respective vertical channel 54. The fins 44 may belongitudinally offset from one another on the base 43 of the sled 42.

With reference to FIG. 9B, another sled 42′ is provided in accordancewith the present disclosure. The sled 42′ includes a central fin 80 thatextends from an upper surface of a base 43 thereof which is sized toslide within the knife channel 56 of the cartridge 50. The central fin80 may include a knife 82 that extends from an upper surface of thecentral fin 80 which is configured to sever tissue joined together bythe staples 60 as detailed below. The sled 42′ also includes fins 44that extend from the upper surface of a base 43 laterally spaced on fromand on both sides of the central fin 80. As detailed above, the fins 44have first and second angled surfaces 45 a, 45 b. The fins 44 on eachside of the central fin 80 are longitudinally and laterally spaced apartfrom one another. Examples of such sleds are disclosed in the '074Patent.

Referring to FIGS. 4, 7, and 10, a method of joining tissue with the endeffector 30 is disclosed in accordance with the present disclosure. Theend effector 30 is positioned over tissue in the spaced apartconfiguration with the tissue positioned between the upper and lowerjaws 40, 90. The upper and lower jaws 40, 90 are then approximated tograsp tissue between the upper and lower jaws 40, 90. With tissuegrasped between the upper and lower jaws 40, 90, the sled 42 istranslated distally through the cartridge 50 such that the fins 44directly engage the backspans 64 of the staples to eject the staples 60from the cartridge 50 as shown in FIG. 10. Specifically, the firstangled surface 45 a of a respective fin 44 engages the chamfered surface66 of a backspan 64 of a staple 60 to eject the staple 60 from thestaple cartridge 50 (i.e., move the staple 60 towards the anvil 92). Asthe staple 60 is ejected from the staple cartridge 50, the legs 62 ofthe staple 60 are driven through the tissue grasped between the upperand lower jaws 40, 90 until the tips 63 of the legs 62 engage the staplepockets 94 of the anvil 92 of the upper jaw 90. As the tips 63 engagethe staple pockets 94, the second angled surface 45 b of the respectivefin 44 engages the chamfered surface 66 of the backspan 64 to drive thestaple 60 into the anvil 92 such that the legs 62 of the staple 60 aredeformed to form the staple 60 (e.g., deform into a B-shape) and jointhe tissue together.

The backspan 64 of the staple 60 is configured to maintain asubstantially parallel relationship with a tissue contacting surface 51of the staple cartridge 50 as the staple 60 is ejected from thecartridge 50 and driven into the anvil 92. Specifically, as detailedabove, the backspan 64 has a substantially rectangular cross-sectionsuch that the vertical sides 65 b of the backspan 64 slide within thevertical slot 52, and the backspan 64 has a length substantially equalto the vertical slot 52 such that the backspan 64 maintains a horizontalconfiguration as the staple 60 is ejected from the vertical slot 52. Inaddition, the legs 62 of the staple 60 may resist deformation adjacentthe backspan 64 such that the legs 62 maintain a horizontalconfiguration of the staple 60 as the staple 60 is ejected from thevertical slot 52.

As the sled 42 is translated through the cartridge 50 to eject thestaples 60 from the cartridge 50, a knife (not shown) is translatedthrough the knife slot 56 to sever the tissue grasped between the upperand lower jaws 40, 90 between the inner rows of vertical slots 52. Theknife trails the fins 44 of the sled 42 such that the knife severs thetissue after the staples 60 are formed to join the tissue. Such aconfiguration may reduce bleeding and enhance the severing of tissue asthe knife is translated through the knife slot 56.

When the sled 42 reaches an end of the sled channel 58 and all thestaples 60 are ejected and formed to join the tissue, the upper andlower jaws 40, 90 are opened to the spaced-apart configuration torelease the joined tissue. The end effector 30 is then withdrawn fromthe surgical site. After the end effector 30 is withdrawn from thesurgical site, the loading unit 10 (FIG. 1A) may be detached from thesurgical instrument (e.g., surgical instrument 101, 201). With theloading unit 10 separated from surgical instrument, the loading unit 10may be sterilized for reuse in another surgical procedure and anotherloading unit 10 may be secured to the surgical instrument to joinadditional tissue in the manner detailed above. Alternatively, after theloading unit 10 is withdrawn from the surgical site, the cartridge 50may be detached from the lower jaw 40 and the lower jaw 40 may bereloaded with a new cartridge 50 to join additional tissue in the mannerdetailed above.

While several embodiments of the disclosure have been shown in thedrawings, it is not intended that the disclosure be limited thereto, asit is intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Any combination ofthe above embodiments is also envisioned and is within the scope of theappended claims. Therefore, the above description should not beconstrued as limiting, but merely as exemplifications of particularembodiments. Those skilled in the art will envision other modificationswithin the scope of the claims appended hereto.

What is claimed:
 1. An end effector comprising: a first jaw including asled; a second jaw including an anvil, the first and second jawsmoveable relative to one another; and a cartridge disposed on the firstjaw and having a plurality of staples, the sled configured to engageeach staple of the plurality of staples to eject the plurality ofstaples from the cartridge as the sled is longitudinally translatedthrough the cartridge.
 2. The end effector according to claim 1, whereinthe end effector is configured to fit through a 5 mm opening when in anapproximated configuration.
 3. The end effector according to claim 1,wherein the cartridge defines a plurality of vertical slots and a firstvertical channel, and wherein the lower jaw defines a longitudinal axis,the first vertical channel parallel to the longitudinal axis, the firstvertical channel passing through each vertical slot of a first line ofthe plurality of vertical slots.
 4. The end effector according to claim3, wherein a staple of the plurality of staples is disposed in eachvertical slot of the plurality of vertical slots.
 5. The end effectoraccording to claim 4, wherein the cartridge and the first jaw define asled channel, the sled longitudinally translatable through the sledchannel.
 6. The end effector according to claim 5, wherein the sledincludes a first fin extending from an upper surface of the sled, thefirst fin translatable through the first vertical channel to engage eachstaple disposed within the vertical slots of the first line of theplurality of vertical slots.
 7. The end effector according to claim 3,wherein each vertical slot of the plurality of vertical slots has afirst width transverse to the longitudinal axis and the first verticalchannel has a second width transverse to the longitudinal axis, thesecond width being less than the first width.
 8. The end effectoraccording to claim 7, wherein a staple of the plurality of staples isdisposed in each vertical slot of the plurality of vertical slots andhas a staple width, transverse to the longitudinal axis, that is lessthan the first width and greater than the second width such that eachstaple is limited to movement towards and away from a tissue contactingsurface of the cartridge.
 9. The end effector according to claim 8,wherein each staple of the plurality of staples includes legs connectedby a backspan, the backspan having a chamfered surface on a proximal endthereof, the chamfered surface disposed at a chamfer angle relative to abottom surface of the backspan.
 10. The end effector according to claim9, wherein the sled includes a first fin extending from an upper surfaceof the sled, the first fin having a first angled surface disposed at afirst angle relative to the upper surface of the sled, the first angledsurface configured to engage the chamfered surface of each staple of theplurality of staples as the sled is translated through the cartridge.11. The end effector according to claim 10, wherein the first angle isequal to the chamfer angle.
 12. The end effector according to claim 10,wherein the first fin includes a second angled surface proximal of thefirst angled surface, the second angled surface defining a second anglewith the upper surface of the sled, the second angle greater than thefirst angle, the second angled surface configured to engage thechamfered surface of each staple subsequent to the first angled surfaceengaging the chamfered surface of each staple.
 13. A loading unitcomprising: an elongated body having proximal and distal ends; and anend effector disposed at the distal end of elongated body, the endeffector including: a first jaw including a sled; a second jaw includingan anvil, the first and second jaws moveable relative to one another;and a cartridge disposed on the first jaw and having a plurality ofstaples, the sled configured to directly engage each staple of theplurality of staples to eject the plurality of staples from thecartridge as the sled is longitudinally translated through thecartridge.
 14. The end effector according to claim 13, wherein theelongated body is configured to fit through a 5 mm opening.
 15. The endeffector according to claim 13, wherein the end effector is articulablerelative to the elongated body.
 16. A method of joining tissue, themethod comprising: clamping tissue between first and second jaws of asurgical instrument; and translating a sled through a cartridge of thefirst jaw, the sled contacting each staple of a plurality of staples toeject the plurality of staples from the cartridge towards the secondjaw.
 17. The method according to claim 16, wherein translating the sledthrough the cartridge includes translating the sled through a sledchannel defined by the first jaw and the cartridge such that a first finextending from an upper surface of the sled contacts each of theplurality of staples.
 18. The method according to claim 17, whereintranslating the sled through the cartridge includes translating thefirst fin through a vertical channel and a first line of vertical slotsdefined by the cartridge, the first line of vertical slots disposedalong the vertical channel.
 19. The method according to claim 17,wherein contacting each staple of the plurality of staples with thefirst fin includes contacting a chamfered surface of each staple of theplurality of staples with a first angled surface of the first fin andsubsequently contacting the chamfered surface of each staple of theplurality of staples with a second angled surface of the first fin. 20.The method according to claim 19, wherein contacting the chamferedsurface of each staple of the plurality of staples with the first angledsurface ejects each staple of the plurality of staples from thecartridge such that legs of the staple penetrate tissue between thefirst and second jaws, and contacting the chamfered surface of eachstaple of the plurality of staples with the second angled surface drivesthe legs of each staple of the plurality of staples into an anvil on thesecond jaw to deform the legs to join the tissue.